High voltages and LEDs off [solved]

Toki · 1845

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Offline Toki

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on: October 06, 2013, 01:40:09 PM
Hi All,

After spending the better part of my weekend putting together my Crack I've finally gotten around to checking the voltages and turning it on.

I've noticed that several of my voltages are significantly higher than expected and the two LEDs on smaller tube are not lighting up. Both tubes however are turning on and I've re-checked all the steps in the manual to verify nothing is mis-connected. All resistances listed in the manual are also correct.

Terminal| My voltages (expected):
1  | 142 (90)
2  | 160 (170)
3  | 0 (0)
4  | 160 (170)
5  | 142 (90)
6  | 0 (0)
7  | 140 (100)
8  | 0 (0)
9  | 140 (100)
10| 0 (0)
11| 0 (0)
12| 0 (0)
13| 160 (170)
14| 0 (0)
15| 185 (185)
20| 0 (0)
21| 212 (206)

A1| 144 (90)
A2| 0 (0)
A3| 13 (1.5)
A4| 0 (0)
A5| 0 (0)
A6| 144 (90)
A7| 0 (0)
A8| 11 (1.5)
A9| 0 (0)

B1| 142 (90)
B2| 160 (170)
B3| 142 (100)
B4| 142 (90)
B5| 160 (170)
B6| 140 (100)
B7| 0 (0)
B8| 0 (0)

newbielink:http://postimg.org/image/w6784cpcz/full/ [nonactive]

For the hell of it I also hooked it up to my DAC and received no sound, for what it's worth. Any help is greatly appreciated.

Thanks!
« Last Edit: October 07, 2013, 07:57:15 AM by Caucasian Blackplate »



Offline sjeffrey

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Reply #1 on: October 06, 2013, 02:59:15 PM
Sounds almost exactly like what I had yesterday.  No LEDs and 140V where they should have been 90V.  Only difference is your input tube is glowing while mine was not.  My issue was the solder at A9 wasn't good which prevented Socket A from getting power.  I can see your A3 and A8 readings are getting power so probably not the same issue as me.  Make sure LEDs are oriented properly.  The silver band should be on the center side or away from A3 and A8.

If orientation is fine then make sure you check each solder with an iron.  A visual check might not reveal the problem.



Offline Paul Birkeland

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Reply #2 on: October 06, 2013, 07:23:08 PM
There's a black ground wire that goes to the center lug on the 9 pin socket.  This wire is missing on your amp and causing all your problems.

(Thanks for posting pictures BTW, super helpful!)

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Toki

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Reply #3 on: October 07, 2013, 07:53:37 AM
Yup, that fixed it. Ah, sweet glorious music.

Thank you guys so much!



Offline sjeffrey

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Reply #4 on: October 07, 2013, 04:21:05 PM
Glad you got it working.
I was just looking at a zoomed in version of your picture and it looks like most of your leads were left untrimmed.
It's a good idea to clip those so nothing shorts out.  Especially between B7-B8, it looks pretty damn close and from memory those are the power wires that feed both sockets.  And it's a good idea to wear glasses when you clip those as they tend to fly off and you dont want to catch one in the eye.